1. Field of the Invention
The present invention generally relates to hose couplings. More particularly, this invention is directed to a hose coupling shroud that increases the reliability and safety of hose couplings of the type used to couple hoses through which abrasive media or air flows at high pressures.
2. Description of the Prior Art
Safety shields for cable, pipe and hose couplings have been suggested in the prior art for increasing the reliability and safety of such couplings. For example, U.S. Pat. No. 3,290,064 to Bush discloses a cable coupling shield that is designed to provide an air-tight seal around a cable coupling, such that inert gas may be contained within the shield to prevent the inflow of destructive agents, such as oxygen. Other prior art shields have been employed to protect tubing and pipe joints, such as in the oil and gas drilling industries. For instance, U.S. Pat. No. 4,615,543 to Cannon discloses a latch-type tubing protector adapted to enclose and protect a tubing joint through which oil or gas is transported to the ground surface from a bore hole. The tubing protector includes lugs and shoulders at its opposite ends to retain the tubing joints within the shroud. Still other types of coupling shields are adapted to capture a corrosive fluid leaking from a pipe joint. An example of such a shield is disclosed in U.S. Pat. No. 5,312,137 to Nee. Nee's safety shield forms an enclosure chamber around a pipe joint, and includes ribs running longitudinally along the interior wall of the shield to provide structural reinforcement. Discharge tubes are provided through which accumulated fluid can be removed from the enclosure.
In addition to those noted above, couplings of one type or another have been employed to protect hose couplings for a variety of applications. The structural integrity and reliability of a hose coupling are particularly critical if the substance flowing through the hose would pose a hazard to bystanders if uncontrollably discharged from the coupling in the event of a coupling failure. One such application is sandblasting performed at construction sites, where a number of large interconnected hoses are used to transport an abrasive material, such as steel shot or sand, at high pressures (e.g., about 150 psig) and velocities. Generally, the hoses are joined by corresponding male and female couplings, termed "knuckles," permanently secured to the ends of the hoses. A shortcoming of such knuckles is that they are often bulky, and therefore prone to becoming caught on obstacles as the hoses are being pulled through job site. As such, the user must spend time untangling or unsnagging the knuckles, which reduces the efficiency of the operation. Occasionally, the knuckles become unintentionally uncoupled when snagged or while the user is trying to unsnag the knuckles. The result is that media is uncontrollably released from the end of the hose remaining connected to the supply pump. Because the abrasive media is under high pressure, the free end of the supply hose not only poses a serious danger to bystanders as a result of the high-velocity media being propelled at high velocities, but the hose end is dangerous as it tends to whip violently to and fro. In addition to the potential for the knuckles to become accidentally uncoupled, knuckles occasionally fail catastrophically, either through wear, fatigue or design limitations.
Although shields of the types disclosed by Bush, Cannon and Nee may be suitable for their respective applications, such shields are not well suited to protect sandblasting hose knuckles. Bush's elastic and air-tight shield would be prone to rupturing, particularly when impinged by the abrasive media flowing through a sandblasting hose. Though the lugs and shoulders present in Cannon's shield would allow venting of an abrasive media between the hose and the ends of the shield, and therefore overcome the shortcoming noted for Bush, high-velocity flow of the abrasive around the lugs and shoulders would rapidly erode the lugs and shoulders to the extent that the hoses could eventually pull free of the shield. Finally, while Nee's shield would appear to be capable of containing a catastrophic failure of a sandblasting hose knuckle, the shield is far too bulky to be suitable for use at job sight having numerous obstacles past which the hose must be routed.
From the above, those skilled in the art will appreciate that what is needed is an improved device for protecting a hose coupling of the type through which abrasive materials flow at high pressures. Such a device would preferably be capable of protecting the coupling from damage, while restraining the coupling and containing the abrasive media in the event of a catastrophic failure. In addition, such a device would preferably have a low profile so as not to promote snagging or entanglement of the hose on obstacles in the work environment. Finally, it would be desirable if the device were capable of immediately notifying a bystander of a coupling failure without endangering the bystander.